Question

我有一些示例数据的下表：

表格：TblTestDB

CREATE TABLE TblTestDB (id int,name varchar(100));

INSERT INTO TblTestDB VALUES(1,'Sam'),(2,'Jack'),
                            (3,'Rock'),(4,'Don'),(5,'Tam');

表格：TblDB1

CREATE TABLE TblDB1 (id int,name varchar(100));

INSERT INTO TblDB1 VALUES(1,'Sam'),(2,'Jack'),
                         (3,'Rock');

表格：TblDB2

CREATE TABLE TblDB2 (id int,name varchar(100));

INSERT INTO TblDB2 VALUES(1,'Jazz'),(2,'Dsouze'),
                         (3,'Rock'),(4,'Jack');

表格：TblDB3

CREATE TABLE TblDB3 (id int,name varchar(100));

INSERT INTO TblDB3 VALUES(1,'Sam'),(2,'Jazz'),
                         (3,'Rock');

我想以以下形式显示结果

TableName   Name    ID
------------------------------
TblDB1      3       3
TblDB2      2       4
TblDB3      2       3

关于结果集的解释：我想显示在表TblTestDB和其他表（TblDB1，TblDB2，TblDB3）之间匹配的列值计数。

尝试以下查询：

查询：

SELECT DB,MAX(Name) AS Name, MAX(ID) AS ID
FROM
(
    SELECT 'TblDB1' AS DB,COUNT(a.Name) AS Name,0 AS ID 
    FROM TblTestDB a
    INNER JOIN TblDB1 b ON a.Name = b.Name
    UNION
    SELECT 'TblDB2' AS DB,COUNT(a.Name) AS Name,0 AS ID 
    FROM TblTestDB a
    INNER JOIN TblDB2 b ON a.Name = b.Name
    UNION
    SELECT 'TblDB3' AS DB,COUNT(a.Name) AS Name,0 AS ID 
    FROM TblTestDB a
    INNER JOIN TblDB3 b ON a.Name = b.Name
    UNION
    SELECT 'TblDB1' AS DB,0 AS Name,COUNT(a.ID) AS ID 
    FROM TblTestDB a
    INNER JOIN TblDB1 b  ON a.ID = b.ID
    UNION
    SELECT 'TblDB2' AS DB,0 AS Name,COUNT(a.ID) AS ID 
    FROM TblTestDB a
    INNER JOIN TblDB2 b  ON a.ID = b.ID
    UNION
    SELECT 'TblDB3' AS DB,0 AS Name,COUNT(a.ID) AS ID 
    FROM TblTestDB a
    INNER JOIN TblDB3 b ON a.ID = b.ID
) a
GROUP BY DB

问题：我可能会得到10列以上的矩阵/数据透视图，上面的查询随着列列表的增长而增加。任何使其简短和简单的更好方法。

Answer 1

SELECT DISTINCT 'TblDB1' AS DB
      ,COUNT(CASE WHEN a.Name = b.Name THEN 1 ELSE NULL END) AS Name
      ,COUNT(CASE WHEN a.ID = b.ID THEN 1 ELSE NULL END) AS ID 
FROM TblTestDB a
CROSS JOIN TblDB1 b
UNION ALL
SELECT DISTINCT 'TblDB2' AS DB
      ,COUNT(CASE WHEN a.Name = b.Name THEN 1 ELSE NULL END) AS Name
      ,COUNT(CASE WHEN a.ID = b.ID THEN 1 ELSE NULL END) AS ID 
FROM TblTestDB a
CROSS JOIN TblDB2 b
UNION ALL
SELECT DISTINCT 'TblDB3' AS DB
      ,COUNT(CASE WHEN a.Name = b.Name THEN 1 ELSE NULL END) AS Name
      ,COUNT(CASE WHEN a.ID = b.ID THEN 1 ELSE NULL END) AS ID 
FROM TblTestDB a
CROSS JOIN TblDB3 b

Answer 2

这够简单吗？

SELECT 
    tableName, sum(s.[Name]) as ncnt, max(s.id) as ID
FROM TblTestDB t
cross apply (
    SELECT tableName, count(name) as [name], max(id) as ID
    FROM (
        SELECT 'TblDB1' as tid, * FROM TblDB1
        union
        SELECT 'TblDB2' as tid, * FROM TblDB2
        union
        SELECT 'TblDB3' as tid, * FROM TblDB3
    ) i
    where i.name = t.name
    group by tableName
) s
group by tableName

不确定您的意思是：“我可能会得到10多个列来显示类似矩阵/数据透视图”。例如，如果您要添加一个“姓氏”列，应该单独匹配还是与“名称”列组合使用？（前者可能会变得有点复杂...）

计算匹配值并以矩阵形式显示

2 个答案: